This week in caching: cache-key normalization wins

This week in caching: cache-key normalization wins

Fragmented cache keys silently tank hit rate. The fixes:

— Affiliate site — every inbound link carried different ?utm/?ref params, so the CDN cached a separate copy per variant; normalizing the key to ignore marketing params lifted hit rate from 52% to 90% with no content change.
— Store — sorting query params (?a=1&b=2 vs ?b=2&a=1) before keying merged duplicate cache entries; cache storage dropped 30%.
— Media — stripping Accept-Encoding variance and serving one Brotli/gzip negotiated copy cut redundant cache objects in half.

The insight: the CDN caches per exact key. Two URLs that render the same page but differ by a tracking param are two cold caches.

Bookmark: Cloudflare Cache Keys / 'Ignore Query String' settings — audit what's actually in your key.